The Lymphatic System and Lymphoid Organs and Tissues Flashcards
Two independent parts of the Lymphatic System are:
Lymphatic Organs and tissues
What is allows to enter the Lymphatic capillaries:
Proteins, fluids viruses, bacteria, cells, cell debris
Characteristics of Lymphatic Capillaries:
1. Bundles of collagen filaments anchoring endothelial cells so that increased interstitial fluid will open flaps instead of collapsing vessel
Specialized lymphatic capillaries that are found on villi of the small intestinal mucosa
Purpose of lacteals?
Drains lymph from the digestive tract, which is milky, due to the digested fats/lipids in the intestines (Chyle)
Travel for Lymph?
Lymphatic - capillaries to collecting vessels to trunks to ducts (Right Lymphatic and Thoracic ducts)
Where are Lymphatic capillaries located?
Are widespread except in the bone, bone marrow, Central Nervous System, and teeth.
What helps Lymph travel to heart?
1) Respiratory and muscular pumps
2) Pulsating of arteries - lymph vessels travel next to blood vessels
3) Smooth muscle in ducts and trunks contract rhythmically to help pump it towards heart
4) movement of adjacent tissues increases flow of lymph towards heart - movement of body
Function in the immune system
1) Located in Lymphnoid tissues
2) Phagocytize foreign substance
3) Activate T-lymphocytes
Involved in the initiation of the immune response
Fibrooblast-like cells; produce a network that supports other cell types in lymphnoid organs
Characteristics of Lymphoid Tissues
1) form an important part of the immune system
- provide a place for lymphocytes to reside and proliferate
- provide a place for lymphocytes and macrophages to monitor the body of foreign substances
2) is a type of loose connective tissues called Reticular loose CT
- macrophages live on the fibers of the network
- lymphocytes reside within the spaces of the network
Where to Lymphoctyes travel in the body?
The circulate between blood vessels, lymphoid and other tissues.
Two types of lymphoid tissues?
1) Diffuse Lymphatic tissues
2) Lymphatic follicles - (Nodules)
Characteristics of Diffuse lymphatic tissue:
1) Consists of a few scattered elements of reticular tissues
2) Found in small amounts in all body organs
3) Found in large amounts in mucous membrane and lymphoid organs
Characteristics of Lymphatic follices (Nodules)
1) Usually have a solid, spherical body without a capsule
2) consists of tightly packed reticular elements and calls
3) Often found within lymphoid organs like lymph nodes
4) May be found as isolated clusters of lymphatic follices - (Peyer's Patch and in the appendix)
What are Lymphoid Organs?
Encapsulated collections of diffuse lymphoid tissue and follicles
Functions of Lymph Nodes?
1) to filter lymph by the use of Macrophages
2) Lymphocytes monitor lymph for antigens and mount and attack again them
Characteristics of Lymph Nodes?
Node is divided into 2 areas:
1) Cortex - contains densely packed follicles and lymphocytes
2) Medulla - contains macrophages on the reticular fibers
Lymph Nodes may add lymphocytes to the lymph to remove foreign matter
If the first lymph along a vessel does not remove all of the foreign material, the next lymph node will. (examine chain to see how far cancer cells have spread.
Passage of infectious organisms through a lymph nodes can cause lymph nodes to swell
From this swelling, one might be able to pinpoint where the infection is.
Characteristics of Lymphoid Tissues:
1) All are made of reticular connective tissues
2) All help protect the body against foreign invaders
3) Only the lymph nodes filter lymph
4) Other lymphoid organs (other than lymph nodes) have efferent lymphatic vessels that drain from them but do NOT have afferent lymphatic vessels
1) Served by large splenic vein and artery
2) Cleanses the body of old and defective RBCs and platelets
3) Removes debris, viruses, bacteria, toxins flowing through its sinuses
1) Secretes Tymosin and Thypoietin
2) Causes T lymphoctyes to become immunocompetent; which enables them to function against specific pathogens in the immune response
1) Palantine, lingual, pharyngeal tonsils
2) Gather and remove many pathogens entering the pharynx in inhaled food or air